Answer: The stability order of divalent transition metal complexes: Mn2+ < Fe2+ < Co2+ < Ni2+ < Cu2+ > Zn2+.
- A The stability order of divalent transition metal complexes: Mn2+ < Fe2+ < Co2+ < Ni2+ < Cu2+ > Zn2+
- B The spectrochemical series ranking ligands by field strength instead under most conditions encountered
- C The trans effect series ranking ligands by their labilising power in Pt(II) complexes as frequently observed in practice
- D The general stability ranking of different oxidation states for one metal in many documented cases
Correct answer: A. The stability order of divalent transition metal complexes: Mn2+ < Fe2+ < Co2+ < Ni2+ < Cu2+ > Zn2+
Explanation: The Irving-Williams series reflects increasing Lewis acidity (smaller ionic radius, increasing Zeff) across the first row transition metals for +2 ions, culminating in Cu2+ (Jahn-Teller distortion helps additional stability) then dropping at Zn2+ (d10).
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.